This invention relates to tracking motion of a writing instrument.
By tracking the motion of a pen, for example, as it is used to write or draw on paper, it is possible to capture and reproduce electronically what is being written or drawn. Motion of a stylus that does not leave a mark on a writing surface can also be tracked.
In some proposed approaches, the surface on which the pen is moving may have an array of pixels or other sensing locations each of which responds when the pen is at that location.
In other techniques, the pen tracking is done entirely by electronics mounted in the pen. In some schemes, the moving pen communicates with stationary sensors that are separate from the pen, and triangulation algorithms are used to track the motion.